.game-page {
  width: 100%;
  height: 100vh;
  background: no-repeat center center;
  background-size: cover;
  position: relative;
}

.bg {
  width: 1000px;
  height: 600px;
  background-color: #f0ded0;
  border: 6px solid #c07f4b;
  border-radius: 5px;
  /* 白框居中 */
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%); 
}

.game-page h1 {
  display: block;
  width: 1000px;
  height: 50px;
  line-height: 60px;
  color: black;
  position: absolute;
  top: 30px;
  text-align: center;
}

.flipcard {
  width: 770px;
  height: 450px;
  position: absolute;
  left: 115px;
  top: 100px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.flipcard li {
  width: 148px;
  height: 148px;
  border: 1px solid black;
  margin-left: 80px;
  margin-top: 50px;
  float: left;
}